Hi! I am a roller main and I came to talk about rollers!
Specifically, I would like to comment on two beautiful beasts: The Splat Roller and the Carbon Deco. Viewing your tier list, it appears the former used to be S and was dropped to A. The Deco however was added to S. I personally think this should be swapped. And here's why:
The vanilla Splat Roller can hold its own in every single gamemode in X lobbies quite well, provided it's user knows what's going on. It damages more heavily on further range than the Carbon, it has easier ways to "get in there" with the curling bomb. And the Splashdown, well, you know what it is.
What the Carbon Deco has going for it is the burst bombs and the chicken rush. Like everyone else, I was hyped for it. Burst bombs and tons of chicken? Amazing, right? Nah, it's less scary than expected. The Carbon Deco seems to be way too situational. The kill range is shorter but of course you will argue there's burst bombs for that. That's true to an extend, but the Splat Roller doesn't even need them. You can pull whole team wipes off with the vanilla roller way easier than with the Carbon, because what the Carbon ironically needs is ink. A lot of it, if you're going to try to take everyone out. What about chicken run? Well, I thought it would be dreadful, but like with anything that does not need a lot of skill, it seems to be less dangerous than I thought it would. You can spam a Zone with it
Lastly, there's the classic Ninja Squid roller loadout going for the vanilla version. You can travel around and take down enemy after enemy if you do it right. You can run the Deco with Ninja Squid too, but you'll then have to compensate for the ninja squid slowdown while you already need all those spots for ink saver sub...
Don't get me wrong. The Carbon Deco is amazing. But it's limits are just more quickly reached than those of the vanilla roller, despite all the heavy nerfs it has been hit with in the update.